No, a 1991 Jeep Wrangler doesn't have an easily accessible "check engine light" reset button like some later model vehicles. The check engine light (or malfunction indicator lamp, MIL) on a 1991 Wrangler indicates a problem detected by the onboard diagnostic system (OBD-I), which is very basic compared to later systems. The light will typically turn off after a certain number of successful engine start cycles *after* the problem is resolved. Simply disconnecting the battery for a short time will clear the light, but this will not fix the underlying problem, and the light will likely come back on if the problem persists.
Therefore, while you don't need a special tool to *turn off* the light, you do need to diagnose and fix the actual problem causing the light to illuminate in the first place. A code reader (for OBD-I) might help identify the problem, but even a simple voltmeter and some basic mechanical knowledge can go a long way.
